1. Field of the Invention
The present invention relates to a processing apparatus, which processes a target substrate such as a silicon wafer used as a material of a semiconductor device, and a transferring apparatus and a transferring method used for the processing apparatus, in particular, to the processing apparatus that deposits various types of films on the front surface of a target substrate and the transferring apparatus and the transferring method used for the processing apparatus that deposits various types of films on the front surface of a target substrate.
2. Description of the Related Art
In a fabricating method for a semiconductor device that has been widely and conventionally used, various types of thin films such as an oxide film, a nitride film, and a nitrogen oxide film are deposited in a predetermined sectional shape on the front surface of a silicon wafer (that is hereinafter simply referred to as “wafer”). Such various types of thin films are deposited by for example a CVD (Chemical Vapor Deposition) unit. As a method for laminating a plurality of thin films on a wafer, a so-called multi-chamber type fabricating apparatus is known. In the multi-chamber type fabricating apparatus, a plurality of CVD units are connected with a single transferring chamber. FIG. 28 is a plan view showing an outlined structure of a typical multi-chamber type processing apparatus 300.
In the multi-chamber type processing apparatus 300, a plurality of processing units 310 to 315 that deposit respective thin films are radially disposed on the outer periphery of a transferring chamber 301 disposed nearly at the center of the apparatus 300. Transferring arms 303 and 304 are disposed in the transferring chamber 301. After a carrier cassette C that contains a plurality of untreated wafers W is placed on a holding table 305, the processing apparatus 300 is activated. First of all, a sub arm 306 takes out a wafer W from the carrier cassette C and temporarily places the wafer W in a load lock chamber 307. Thereafter, the transferring arm 303 is operated to take out the wafer W from the load lock chamber 307 and convey the wafer W to the transferring chamber 301. The transferring arm 303 loads and unloads the wafer W between each of the processing units 310 to 315 and the transferring chamber 301 in a predetermined sequence so that a plurality of thin films are deposited on the wafer W.
In recent semiconductor apparatuses, there are needs to increase the number of films to be deposited and to decrease the thickness thereof. However, when the number of thin films is increased, the forgoing six-chamber type processing apparatus 300 that has six processing units cannot deposit all the desired thin films. To solve such a problem, a plurality of six-chamber type processing apparatuses such as multi-chamber type processing apparatuses 300 are disposed. In this case, after films are deposited on a wafer w by one processing apparatus, the wafer W is removed therefrom and conveyed to the adjacent processing apparatus in which other films are deposited on the wafer W.
However, when a wafer W on which a thin film is being deposited in a process atmosphere is exposed to outer air, an oxide film is formed on the front surface of the wafer W. Thus, a step that removes the oxide film is additionally required. In other words, the fabrication efficiency deteriorates. In addition, since thinner films are required, when a wafer W is taken out from a process atmosphere, a thin film deposited on the front surface of the wafer W deteriorates. As a result, the quality of the semiconductor device as a final product deteriorates. In addition, when two multi-chamber type processing apparatus 300 are disposed, the installation area (the footprint) becomes large. As a result, the facility cost and the fabrication cost of the final product rise.